document.write( "Question 618965: John is 7 times older than Sally in 10 years their combined age will be 71. How old is John \n" ); document.write( "

Algebra.Com's Answer #389208 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+j+\"$ = John's age now
\n" ); document.write( "Let $\"+s+\"$ = Sally's age now
\n" ); document.write( " $\"+j+%2B+10+\"$ = John's age in 10 years
\n" ); document.write( " $\"+s+%2B+10+\"$ = Sally's age in 10 years
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+j+=+7s+\"$
\n" ); document.write( "(2) $\"+j+%2B+10+%2B+s+%2B+10+=+71+\"$
\n" ); document.write( "----------------------
\n" ); document.write( "(2) $\"+j+%2B+s+=+71+-+20+\"$
\n" ); document.write( "(2) $\"+j+%2B+s+=+51+\"$
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+7s+%2B+s+=+51+\"$
\n" ); document.write( "(2) $\"+8s+=+51+\"$
\n" ); document.write( "(2) $\"+s+=+6.375+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+j+=+7%2A6.375+\"$
\n" ); document.write( "(1) $\"+j+=+44.625+\"$
\n" ); document.write( "Note that $\"+.625%2A12+=+7.5+\"$
\n" ); document.write( "John is 44 years and 7 and 1/2 months old
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"+j+%2B+s+=+51+\"$
\n" ); document.write( "(2) $\"+44.625+%2B+6.375+=+51+\"$
\n" ); document.write( "(2) $\"+51+=+51+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+j+=+7s+\"$
\n" ); document.write( "(1) $\"+44.625+=+7%2A6.375+\"$
\n" ); document.write( "(1) $\"+44.625+=+44.625+\"$
\n" ); document.write( "OK \n" ); document.write( "

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